In the decades immediately ahead, East Asia will experience perhaps the modern world’s most dramatic demographic shift. All of the region’s main states—China, Japan, South Korea, and Taiwan—are about to enter into an era of depopulation, in which they will age dramatically and lose millions of people. According to projections from the Population Division of the UN Department of Economic Social Affairs, China’s and Japan’s populations are set to fall by eight percent and 18 percent, respectively, between 2020 and 2050. South Korea’s population is poised to shrink by 12…